U.S. patent application Pub. No. US2008/0007533 entitled “Capacitance Sensing Electrode with Integrated I/O Mechanism” (incorporated by reference herein in its entirety) teaches capacitance-based touch sensing.
U.S. Pat. No. 7,495,659 entitled “Touch Pad for Handheld Device” (also incorporated herein by reference) teaches a pixel based touch pad. The touch pad of U.S. Pat. No. 7,495,659 can be considered to be a “single touch” touch pad, i.e., it can be configured to detect a single touch event at any one time. The touch pad of U.S. Pat. No. 7,495,659 does not disclose dynamically changing the granularity of touch pixels.
U.S. patent application Pub. No. US2008/0158172 entitled “Proximity and Multi-Touch Sensor Detection and Demodulation” (also incorporated by reference herein in its entirety) teaches a multi-touch sensing panel which can be combined with a display in a portable device. Thus, interaction between a user and the portable device can be improved, as the user can interact with dynamically displayed images by virtually touching them, moving them, turning them, etc. application Pub. No. US2008/0158172 also describes near field and far-field proximity sensing. Some previously described multi-touch panels (as well as near-field and far-field proximity panels) feature touch sensing elements (or touch pixels) that are of the same size. In other words, they feature touch sensors with uniform granularity.
U.S. Pat. No. 7,812,827 entitled “Simultaneous Sensing Arrangement” (incorporated by reference herein in its entirety) describes a multi-touch panel which initially scans for touch events at a low granularity and then, if it detects touch events in particular regions, scans for them with higher granularities. Thus, the panel of the U.S. Pat. No. 7,812,827 application, while providing that some regions may be initially scanned at lower granularities, still ensures that touch events at the entire panel are eventually scanned and processed at the same granularity.
Each touch pixel of a multi-touch panel can require a certain amount of power. Lower granularity can require less pixels and consequently less power. Minimizing the power usage can be very beneficial for multi-touch enabled devices. This can be especially true for devices having large displays/touch panels. However, in certain instances, a certain level of granularity may be necessary in order to correctly detect touch events.